Quantitative, Regiospecific, and Stereoselective Radical Ring-Opening Polymerization of Monosaccharide Cyclic Ketene Acetals
Quantitative, Regiospecific, and Stereoselective Radical Ring-Opening Polymerization of Monosaccharide Cyclic Ketene Acetals
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DOI：
10.1021/jacs.3c14244
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发表时间：
2024-02-12
影响因子：
15
通讯作者：
Niu，Jia
中科院分区：
文献类型：
--
作者：
Jiang，Na-Chuan;Zhou，Zefeng;Niu，Jia
环烯酮缩醛（CKAs）是自由基开环聚合（rROP）中研究最充分的单体之一。然而，在均聚和共聚中的保留环的副反应和低反应性仍然是现有CKAs的重大挑战。在这里，我们报告说，一类单糖CKAs可以很容易地从一个短的和可扩展的合成路线制备，并可以进行定量，区域特异性和立体选择性的rROP。NMR分析和降解实验揭示了一种反应机制，涉及在吡喃糖的C2位置与不同的单糖表现出不同的立体选择性的自由基加成的单体的传播自由基。此外，马来酰亚胺的加入被发现可以提高单糖CKA在与乙烯基单体共聚中的掺入效率，并产生独特的可降解三元共聚物，其在聚合物主链中具有碳水化合物基序。
Cyclic ketene acetals (CKAs) are among the most well-studied monomers for radical ring-opening polymerization (rROP). However, ring-retaining side reactions and low reactivities in homopolymerization and copolymerization remain significant challenges for the existing CKAs. Here, we report that a class of monosaccharide CKAs can be facilely prepared from a short and scalable synthetic route and can undergo quantitative, regiospecific, and stereoselective rROP. NMR analyses and degradation experiments revealed a reaction mechanism involving a propagating radical at the C2 position of pyranose with different monosaccharides exhibiting distinct stereoselectivity in the radical addition of the monomer. Furthermore, the addition of maleimide was found to improve the incorporation efficiency of monosaccharide CKA in the copolymerization with vinyl monomers and produced unique degradable terpolymers with carbohydrate motifs in the polymer backbone.